Re: [APML] question on exposure times for E200

[Philip Perkins <pgp@astrocruise.com>]

Richard,

This is too late for your shots last night, but for future work you may 
want to see an astrophotography exposure table I produced a while 
back:  http://www.astrocruise.com/astroexp.htm

This was intended to be a starting point for films such as Kodak PPF and PJ 
series.  You would probably need to go longer with E200 - perhaps up to 50% 
(max) but the limiting factor will be sky fog, and that in turn depends 
largely on the object's elevation, sky transparency, and degree of light 
pollution in your area.  Type of film plays a relatively minor role in 
determining exposure time, provided that it's known to be a good astro film 
to start with.  Also ASA rating becomes relatively meaningless once we 
start exposing film for longer than a few seconds, however it can still be 
useful in determining relative graininess of a film.

With E200 at f/6.7 I would probably start with an exposure of 50 minutes 
but I may want to modify that significantly once I knew about the object's 
elevation, sky transparency, and light pollution.

--Philip


At 12:03 10/07/2004 -0700, you wrote:
>Hi gang
>
>I want to do some prime focus film shots tonight in the Saggittarius 
>region using my Pentax 6x7 and some E200 film.
>
>I am really excited about doing this.
>
>I want to mount the camera on my AP180EDT with both the 0.75x 
>telecompressor and the AP field flattener. That gives a focal ratio of f/6.75
>
>My question is what exposure time should I use for something like M20?
>
>If I got no answers from the list, I'd probably go with 45 minutes, but 
>you folks are the experts, so I'd like to hear some other opinions.
>
>Thanks and best regards
>Richard
>
>
>_______________________________________________
>Astro-Photo mailing list
>Astro-Photo@seds.org
>http://seds.org/mailman/listinfo/astro-photo

Philip Perkins
<pgp@astrocruise.com>
Wiltshire UK & Luberon France
www.astrocruise.com

_______________________________________________
Astro-Photo mailing list
Astro-Photo@seds.org
http://seds.org/mailman/listinfo/astro-photo